A criminalist is a person who specializes in the collection and analysis of physical evidence from crimes (criminalistics). A criminalist is usually at work in the crime laboratory. Criminalists identify evidence from the crime scene (discover what it is and what it is made of); they try to determine how or why the evidence was at the scene to attempt to put a perpetrator at the scene and they use the evidence to attempt to reconstruct how the crime happened.
Depending on the location of the crime, either police officers or criminalists will collect evidence from the crime scene for laboratory analysis. A criminalist is also referred to as a “forensic scientist” or a “criminal analyst.” A criminalist should not be confused with a criminologist, who uses sociology to study crime. Television's "CSI" shows have transformed criminalistics into a pop culture subject.